The present invention relates to unmanned air vehicles, and, more particularly, to unmanned air vehicles having retractable wings and controllable nose fairings, and methods of flying unmanned air vehicles with retractable wings and controllable nose fairings.
The field of unmanned air vehicles (UAV) has increasingly required higher performance and new mission capabilities for both military and conventional uses. Generally speaking, improved mission performance often requires adding new mission platforms to a UAV. Additional weapon systems, new imaging capabilities, etc., continue to be added to existing UAVs extending the limits of their operational capability. For example, as a new imaging system or weapon system is added to a UAV, space must be made within the fuselage to accommodate the new platforms. Other platforms may have been removed to accommodate the new platforms. Additional closures, shutters, doors, etc. may also be required that permit the new platform to operate with a previously existing UAV.
Typically, the addition of new mission platforms on UAVs has led to increasing the weight and redistribution of weight on UAVs. As such, the field of UAVs has been tending toward larger and heavier craft in order to accommodate newer mission platforms and multiple missions. One negative effect of this trend has been reduced range capabilities of UAVs. That is to say that increased size and weight has required greater fuel consumption in order to maintain the same range, which in turn requires greater fuel carrying capacity. Manufacturing UAVs with greater fuel carrying capacity has only compounded the need for larger and heavier UAVs.
Solar powered UAVs have been used in experiment and research, yet have not found commercial viability for military or conventional commercial use. It is generally thought that the weight requirements of UAVs preclude further development in the field of solar powered UAVs. The obvious benefit of solar powered UAVs, however, is increased range. Solar powered UAVs that provide increased range which could be designed to carry lighter weight mission platforms may therefore be more versatile than existing UAVs. Accordingly, there is a need in the art for solar powered UAVs with increased capabilities for carrying mission systems and providing increased range over current UAV systems.
Accordingly, an unmanned air vehicle with improved versatility is provided. According to one embodiment of an unmanned air vehicle, the air vehicle comprises a fuselage having port and starboard retractable wings interconnected to the fuselage. At least one propeller and propeller motor, interconnected to each wing are also provided. As used herein, when a device or element is xe2x80x9cinterconnectedxe2x80x9d to another device or element, it may be directly connected, attached, or connected by one or more intervening devices or elements. In one embodiment, a propeller motor includes a propeller motor generator so that the propeller may be permitted to freewheel in order to generate electricity. For example, while the wings are retracted, the port and starboard propellers rotate as a result of the airflow and thereby may be used as motors providing electric current to electronics and other electrical equipment onboard the unmanned air vehicle. For example, the unmanned air vehicle may include a battery for receiving the electric current so that electric energy may be stored for future use and, therefore, provided to the electronics or other electrical equipment onboard the unmanned air vehicle.
According to another embodiment, the unmanned air vehicle includes a movable mass interconnected to the fuselage that is positionable between the forward portion of the fuselage and the aft portion of the fuselage. An actuator moves the movable mass about the fuselage in order to change the center of gravity of the unmanned air vehicle.
One aspect of this unmanned air vehicle includes a nose fairing disposed along the forward portion of the fuselage and typically having port and starboard nose fairings that may pivot about the fuselage. Pivoting nose fairings, therefore, provide aerodynamic flight control and may be individually controlled by a flight control system in order to maneuver the unmanned air vehicle. Another aspect of this invention comprises port and starboard wheels interconnected to outward portions of the port and starboard nose fairings, respectively. As such, the port and starboard nose fairings may be positioned downward to permit the port and starboard wheels to act as landing gear for the unmanned air vehicle.
Another aspect of the unmanned air vehicle also includes a single aft wheel. A single aft wheel for landing and takeoff is interconnected to the fuselage. One aspect of the aft wheel includes a wheel assembly comprising a wheel retainer interconnected to the fuselage, such as by port and starboard wheel fairings. A wheel rim and tire are disposed about the retainer and rotate about circumferentially disposed bearings.
One aspect of the unmanned air vehicle also includes photovoltaic cells, capable of providing an electric current to a battery. The solar powered photovoltaic cell may typically be disposed on an area of the fuselage or wings that will receive sunlight in order to convert sunlight into electrical current for use by other equipment on the unmanned air vehicle.
The unmanned air vehicle of the present invention also permits a method of flying an unmanned air vehicle having retractable wings and nose fairings. According to one embodiment, the method includes pivoting port and starboard nose fairings in order to control the direction of flight of the vehicle. When port and starboard nose fairings are pivoted downwardly, the wheels at the end of the port and starboard nose fairings may be used as landing gear.
Another method of flying an unmanned air vehicle includes retracting port and starboard wings on the unmanned air vehicle and positioning the nose fairings to achieve a downward glide angle toward earth. The mass within the unmanned air vehicle is moved from fore to aft in order to achieve an ascent position of the unmanned air vehicle. The ascent position may be used for weapons delivery, such as from a chemical laser. While the wings are retracted, another aspect of the method permits the propellers to freewheel so that the propellers generate electricity. The electricity can be provided to a battery, electronics or other electrical equipment onboard the aircraft. After the port and starboard wings have been retracted, they may be once again fully extended to a flying position and the port and starboard propeller motor generators reenergized in order to motorize the propellers and provide thrust to the vehicle.